JPS5933638A - Information recording and reproducing system - Google Patents

Abstract

PURPOSE:To ensure stable tracking control as well as recording and reproduction of information, by recording previously tracking synchronizing bits on a disk and detecting a tracking signal produced from said synchronizing bits to record the information signal between the synchronizing bits together with tracking. CONSTITUTION:The difference signal DEF given from a 4-split photodetector passes through a differentiating circuit 60, a zero point detecting circuit 61 and pulse circuits 31 and 32 and turned into edge pulses 31' and 32' of synchronizing bits which are previously recorded on a disk. The level of the sum signal DF23 obtained at that time point is sampled and held by sampling/holding circuits 36 and 37, and the difference between outputs 36' and 37' is obtained by a subtractor 38 to obtain a tracking signal 39. Then the information writing pulse is generated via an edge pulse 32' and a monostable multivibrator 35 to record the information bits 28 among the bits 27 while carrying out tracking with the signal 39. At the same time, the outputs of sample/hold drivers 33 and 34 are set at zero to ensure the stable tracking control as well as the recording/ reproduction of information.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an information recording angle generation method for a recordable and reproducible optical disc.

Conventionally, a DC track groove with a depth of λ/8 is formed on the disk in advance, and tracking signals are generated by utilizing the fact that when the optical spot deviates from the center of the track, the edges of the track groove cause asymmetry in the diffracted light. There is known an apparatus for recording information on a rack groove using a laser modulated by an information signal (DC) while performing track tracking using the tracking signal. In this device, two photodetectors arranged parallel to the track receive the diffracted light beam from the track groove, and a tracking signal is detected by taking the difference in the output of these two photodetectors. . Such a device is shown in Japanese Patent Application Laid-Open No. 49-60702.

In this device, when a light spot is moved by, for example, a galver mirror for tracking control, a tracking offset occurs in the tracking signal.

Furthermore, when the disk is tilted, coma aberration occurs, and this coma aberration particularly disrupts the balance of the two photodetectors arranged parallel to the track, causing more track offsets to occur. This results in the disadvantage that normal track tracking cannot be performed. This tracking signal determines the structure of the C groove on the disk, i.e. the depth and width of the groove.

It is expressed as a function of the wavelength 1 distribution of the light source and the numerical aperture of the lens.

FIG. 8 shows that in the conventional device, the light beam d? 75;DC
It is a figure which shows the tracking signal obtained when it deviates from the center of a groove.

The S parameter of the disk and optical system is wavelength λ = 0.82
μm, groove depth λ/8, IIJO, 45/l m, )
The Rattabitch is 1.6 μm, the Luns opening number is 0.5, the distribution coefficient r"=4, and θ=0.5. As is clear from FIG. 8, the tracking offset is 0.08 μm in this case. Experimentally tJ, 0.08 μm
If there is a secondary offset, stable towing/yielding cannot be performed.

Furthermore, when reproducing a disc on which information is recorded in the DC groove at high density, there is a drawback that the tracking offset increases as the tracking sensitivity decreases.

Moreover, in the case of the conventional I)C groove method in which the recording material is λ/8 deep, the selection 41 becomes narrower, and the range of application becomes wider. In other words, the difference in the reflectance of the de-f-suf, the difference in the unevenness,
There are 2-9 drawbacks that the tracking signal becomes unstable due to the difference in refractive index.

The present invention has been made in view of the above points, and it solves all the problems of the prior art described above, and enables stable one-lack/g control regardless of the monthly recording fee of the disk, and also provides stable information recording and The purpose of the present invention is to provide an information recording and reproducing method that allows +Ir raw data.

In order to achieve this object, the present invention records synchronization pits for tracking on a disk in advance, detects a tracking signal from these synchronization pits, and uses this signal to perform tracking while tracking between synchronization bits. It is characterized by recording information signals.

Embodiments of the present invention will be described below with reference to the drawings. 1st
- Figure 1-a is a diagram showing the configuration of an optical system for recording and reproducing information on an optical disk, and Figure 1-b is a diagram for explaining the principle of driving a semiconductor laser. In a semiconductor laser, by pulse-modulating the drive current level (horizontal axis) from X to X2, it is possible to directly modulate the output level of the laser source (vertical axis) from y to y2. When playing back, set the laser light meter output level to y, and when recording,
Drive with the laser light output level set to y.

Referring to FIG. 1-a, 3 is a driving circuit for the semiconductor laser 4. In FIG. The light beam emitted from the laser 4 passes through a coupling lens 5, a beam splitter 6, and a Garno mirror 7.1/
A potential spot 11 is irradiated onto an information groove 12 of a disk 10 by a four-wavelength plate 8 and an objective lens 9. The reflected light diffracted by the information groove 12 returns to the above-mentioned optical system and is 1/
The light is reflected by the beam splitter 6 due to the polarization effect of the four-wavelength plate 8, and is received by the four-split photodetector 13. Photodetector 13
FIG. 2 shows the structure of the photodetector and its signal processing circuit for obtaining the drugging signal from the photodetector. In Fig. 2, the origin of the photodetector is aligned with the optical axis of the optical system (Fig. 1-a), the X-axis is set parallel to the track direction, and the Y-axis is set in the direction across the track. , 3.4 quadrant photodetector 14
．． 1('i, 15°17ka・ra output signal 114 e
Take out each of I16 + JIB r ■17, DF'= (114+Il!l) - (Illl-1-
117) is added to the adder circuit 18.19 and subtractor 1 "1".
1 path 21, RP'= (114-t-IB+) + (I+6-1
-117) is generated by the adder circuits 18, 19, and 20.

Furthermore, 1) EV = (114+Lt) - (JIB1-'
A difference signal Il+) is generated by the addition circuit 5[), 51 and the subtraction circuit 52.

By supplying the F signal and the DF' signal to the circuit shown in FIG. 4, a tracking signal is generated.

FIG. 3 shows an example of a track recorded according to the present invention. The track 12 is composed of two types of blocks A and 13 silk combinations. Block A has 5YNC focus 24 to apply phase lock, 5YNC to determine the origin of data block B)) A 'I'i' l]
It consists of R and N pits 25. A timing pulse train 26 is created from these 5YNC bits 24 and 5YNC PATTERN pits 25, and using this timing pulse and the synchronization pits 27 recorded in the data block BK, information pits 28 are accurately recorded between the synchronization pits 270. .

Similarly, endogeneity is 5YNC bit 24 and 5YNCpA'r
The timing error 26 and the origin of the data block B are determined from the rI>RN bit 25, and the information pit 28 and synchronization bit 27 are distinguished and generated 111.

Figure 4 is a circuit block diagram for obtaining tracking number 18 using synchronized pits, and Figure 5 is a diagram for explaining the %b operation. A diagram showing the force, IS). When the laser spot 11 hits the synchronization bit 27 on the track 12 in chronological order, the 4-split photodetector 1-4.15°16
．． The sum T of the signals generated from 17? , F = (L4
+I+a) +(II6+I'+7) and difference signal 1) E
F=(II4+Il?) (IB-t■1.) and difference false DF= (I+4+II!l)-(IITl+I
l? ) is the waveform of the RF signal q 22 as shown in FIG.
At rJ, times 1υ1 bit 27, the signal level decreases due to diffraction. 1. ) The F, F signal 62 has a peak when both the synchronization bits 27 are activated, and has a signal waveform that is similar to the F signal divided by rN. I) F (Word 2: 18 depending on the direction in which the 3 light spots 11 pass from the center of the track)
A signal whose phase is inverted by 0 degrees is obtained, and is zero at t9 in the synchronization pit 27, and has a waveform with h peaks at both ends of the pit. Differentiating circuit 60 for D EF No. 18 62
Differentiate with and obtain an output of 60'. Furthermore, this differential output (1
) 60' is determined by the zero point detection circuit 61 as the zero point, 61° (2
) 31.32 gives zero point 61.61...
(In other words, it does not indicate the position of the edge of the synchronization pit 27, but creates Etsunovarus 31' and 32', and then J) F signal 2
3 level, perform a sample hold with the lean pull hold circuit 36°37, and each output crab 36'.

; 17' differential is created by the subtracter 38, and the tracking 18
Find number 39. This tracking signal 39 drives the galver mirror shown in FIG.
) to be at the center of the track 12. On the other hand, in order to record the information pit 28 with a clear modulation pulse 28' between the synchronous pits 27, the synchronous pit 27 is Edge pulse 32' generated at one end
Using this, the one-shot multi 35 generates the information-4 recording timing pulse 2, creating a timing time T, ~T2 for recording the information modulation pulse 28'. Furthermore, in order to prevent the information modulation pulse 28' from disturbing the tracking signal 39 during the information writing timing times T and -T2, the -ripple port output 36' is
, 37' are held in the state at synchronization bit 27. To this end, the write timing pulse 2 is used to make the outputs of the Thumburu bold ML drivers 33 and 34 zero, and to make the Thumburu output bold.

In this way, it becomes possible to insert the information pits 28 between the synchronization pits 27 while detecting the tracking signal from the synchronization bits 27.

FIG. 6 shows the Zumblebold control M shown in FIG.
C33.34 Shows an example of the circuit configuration and its waveform of No. 43, No. 1. The case using the circuit is shown.

FIG. 7 is a diagram showing the relationship between tracking i2i and i and track deviation according to the present invention. According to this, even if the disk is tilted by 0.8 degrees, the offset u: o, 03μ
m or less, and stable tracking is 1j digits.

FIG. 8 shows data for the conventional I)c group with a groove depth of λ/8. Comparing FIGS. 7 and 8, it is clear that the effect of the present invention is remarkable.

As has been discussed hereinabove, according to the information recording internal method of the present invention, it is possible to record information at high density on the disc-1- and to read out the information recorded at high density accurately. Significant progress can be made in the field of use of digital discs, digital audio discs, etc. In the present invention, the conventional λ/
The disadvantage of the method of recording information in the 8-deep '1) C groove, that is, the large tracking offset when the disk is tilted, can be solved. In the case of reproduction, it is also possible to solve the problem that the tracking sensitivity increases as the tracking sensitivity decreases.

In addition, in the conventional method of forming I)C grooves with a depth of λ/8, the selection of recording apertures is narrowed, and the range of application is limited.
However, in the present invention, it is possible to record the difference in reflectance, unevenness, and refractive index as synchronous piping, and tracking (taking out r'i) is possible using inexpensive equipment. can get.

However, the present invention is not limited to the above-described embodiments, but it is possible to make various modifications.

For example, the information grooves formed on the disk are not limited to a spiral shape, but may be concentric circles. Furthermore, information can be recorded onto a disk by using not only a semiconductive laser but also a combination of an external modulator and a gas laser.

Furthermore, the method of distributing No. 111 for synchronization detection on the disk recording leg is not limited to the method of the above-mentioned embodiment, and another time synchronization pulse is recorded between the synchronization bits, and this time synchronization pulse It is also possible to record information without phase shift while taking timing using .

[Brief explanation of the drawing]

Figure 1-A is a diagram showing the optical system used to record information on a disk and generate rli data. -1) t\I to 1
Figure 2 (L: 1) shows the structure of the photodetector [Figure 1, Figure 3 shows the track recorded by the present invention 4 and 5 show one embodiment of the present invention, and FIG. 6 shows an example of a sample anchored control driver used in the present invention. Figures 7 and 8 are diagrams C showing the relationship between track misalignment and tracking signals for the present invention and the conventional example, respectively. ,06 0.12 ρ/3
ρ24 helmet m9F ras 5

Claims (1)

[Claims] 1. A light beam is irradiated onto a rotating recording medium in which synchronization pits are optically formed in advance along the rotational direction on a rotating surface, and the above-described light beam is modulated by the synchronization bits. An information recording and reproducing method characterized in that a tracking signal is detected from a light beam, and while tracking is performed using this signal, information is recorded by irradiating a recording beam modulated by an information signal between synchronization pits and synchronization bits.゛Method. 2. The information recording and reproducing method according to claim 1, wherein a write timing pulse for recording the information is obtained from a light beam modulated by the synchronization pit. 3. The information recording and reproducing method according to claim 2, wherein the tracking signal is held by the write timing pulse. 4. Detecting the center of the synchronization pit from the light beam modulated by the synchronization bit, detecting the tracking signal from this center during a period of time 1J of the synchronization bit, and obtaining the write timing pulse after the period. Claim 2 or 3 characterized by
Information recording and reproducing method described in section.